ScienceShot

Wasp builds nest out of dead ants

A newly discovered insect has been dubbed the bone-house wasp for good reason: Researchers report that it is the only known species to build its nest with dead ants. Whereas other wasps use pieces of arthropods to disguise their nest, the bone-house wasp (Deuteragenia ossarium) is the first to use whole ants, the researchers report this month in PLOS ONE. Scientists discovered the wasp when they traveled to southeast China’s Gutianshan National Nature Reserve and set up trap nests—plastic tubes filled with cutouts of the giant cane plant for the wasps to nest in. Inside, the wasps built brood cells, little cavities with walls made from plant debris, resin, or soil, for their developing young. When the entrance cell was filled with ants, a variety of parasitic wasp and fly species attacked only 3% of brood cells. Nests belonging to wasp species that don’t follow this behavior were parasitized at a rate of 16.5%. The ant species (Pachycondyla astuta) that appeared most often in the wasps’ barricades is abundant, aggressive, and has a mean sting. The researchers hypothesize that the ants’ smell—which lingers after death—functions either to disguise the odor of the wasp’s offspring or to dissuade predators who know better than to pick a fight.